1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4 *****************************************************************************
5 * Copyright (C) 1996-2015, International Business Machines Corporation and
6 * others. All Rights Reserved.
7 *****************************************************************************
8 */
9
10#include "unicode/utypes.h"
11
12#if !UCONFIG_NO_NORMALIZATION
13
14#include "unicode/caniter.h"
15#include "unicode/normalizer2.h"
16#include "unicode/uchar.h"
17#include "unicode/uniset.h"
18#include "unicode/usetiter.h"
19#include "unicode/ustring.h"
20#include "unicode/utf16.h"
21#include "cmemory.h"
22#include "hash.h"
23#include "normalizer2impl.h"
24
25/**
26 * This class allows one to iterate through all the strings that are canonically equivalent to a given
27 * string. For example, here are some sample results:
28Results for: {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
291: \u0041\u030A\u0064\u0307\u0327
30 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
312: \u0041\u030A\u0064\u0327\u0307
32 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
333: \u0041\u030A\u1E0B\u0327
34 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
354: \u0041\u030A\u1E11\u0307
36 = {LATIN CAPITAL LETTER A}{COMBINING RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
375: \u00C5\u0064\u0307\u0327
38 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
396: \u00C5\u0064\u0327\u0307
40 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
417: \u00C5\u1E0B\u0327
42 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
438: \u00C5\u1E11\u0307
44 = {LATIN CAPITAL LETTER A WITH RING ABOVE}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
459: \u212B\u0064\u0307\u0327
46 = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING DOT ABOVE}{COMBINING CEDILLA}
4710: \u212B\u0064\u0327\u0307
48 = {ANGSTROM SIGN}{LATIN SMALL LETTER D}{COMBINING CEDILLA}{COMBINING DOT ABOVE}
4911: \u212B\u1E0B\u0327
50 = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH DOT ABOVE}{COMBINING CEDILLA}
5112: \u212B\u1E11\u0307
52 = {ANGSTROM SIGN}{LATIN SMALL LETTER D WITH CEDILLA}{COMBINING DOT ABOVE}
53 *<br>Note: the code is intended for use with small strings, and is not suitable for larger ones,
54 * since it has not been optimized for that situation.
55 *@author M. Davis
56 *@draft
57 */
58
59// public
60
61U_NAMESPACE_BEGIN
62
63// TODO: add boilerplate methods.
64
65UOBJECT_DEFINE_RTTI_IMPLEMENTATION(CanonicalIterator)
66
67/**
68 *@param source string to get results for
69 */
70CanonicalIterator::CanonicalIterator(const UnicodeString &sourceStr, UErrorCode &status) :
71    pieces(NULL),
72    pieces_length(0),
73    pieces_lengths(NULL),
74    current(NULL),
75    current_length(0),
76    nfd(*Normalizer2::getNFDInstance(status)),
77    nfcImpl(*Normalizer2Factory::getNFCImpl(status))
78{
79    if(U_SUCCESS(status) && nfcImpl.ensureCanonIterData(status)) {
80      setSource(sourceStr, status);
81    }
82}
83
84CanonicalIterator::~CanonicalIterator() {
85  cleanPieces();
86}
87
88void CanonicalIterator::cleanPieces() {
89    int32_t i = 0;
90    if(pieces != NULL) {
91        for(i = 0; i < pieces_length; i++) {
92            if(pieces[i] != NULL) {
93                delete[] pieces[i];
94            }
95        }
96        uprv_free(pieces);
97        pieces = NULL;
98        pieces_length = 0;
99    }
100    if(pieces_lengths != NULL) {
101        uprv_free(pieces_lengths);
102        pieces_lengths = NULL;
103    }
104    if(current != NULL) {
105        uprv_free(current);
106        current = NULL;
107        current_length = 0;
108    }
109}
110
111/**
112 *@return gets the source: NOTE: it is the NFD form of source
113 */
114UnicodeString CanonicalIterator::getSource() {
115  return source;
116}
117
118/**
119 * Resets the iterator so that one can start again from the beginning.
120 */
121void CanonicalIterator::reset() {
122    done = FALSE;
123    for (int i = 0; i < current_length; ++i) {
124        current[i] = 0;
125    }
126}
127
128/**
129 *@return the next string that is canonically equivalent. The value null is returned when
130 * the iteration is done.
131 */
132UnicodeString CanonicalIterator::next() {
133    int32_t i = 0;
134
135    if (done) {
136      buffer.setToBogus();
137      return buffer;
138    }
139
140    // delete old contents
141    buffer.remove();
142
143    // construct return value
144
145    for (i = 0; i < pieces_length; ++i) {
146        buffer.append(pieces[i][current[i]]);
147    }
148    //String result = buffer.toString(); // not needed
149
150    // find next value for next time
151
152    for (i = current_length - 1; ; --i) {
153        if (i < 0) {
154            done = TRUE;
155            break;
156        }
157        current[i]++;
158        if (current[i] < pieces_lengths[i]) break; // got sequence
159        current[i] = 0;
160    }
161    return buffer;
162}
163
164/**
165 *@param set the source string to iterate against. This allows the same iterator to be used
166 * while changing the source string, saving object creation.
167 */
168void CanonicalIterator::setSource(const UnicodeString &newSource, UErrorCode &status) {
169    int32_t list_length = 0;
170    UChar32 cp = 0;
171    int32_t start = 0;
172    int32_t i = 0;
173    UnicodeString *list = NULL;
174
175    nfd.normalize(newSource, source, status);
176    if(U_FAILURE(status)) {
177      return;
178    }
179    done = FALSE;
180
181    cleanPieces();
182
183    // catch degenerate case
184    if (newSource.length() == 0) {
185        pieces = (UnicodeString **)uprv_malloc(sizeof(UnicodeString *));
186        pieces_lengths = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
187        pieces_length = 1;
188        current = (int32_t*)uprv_malloc(1 * sizeof(int32_t));
189        current_length = 1;
190        if (pieces == NULL || pieces_lengths == NULL || current == NULL) {
191            status = U_MEMORY_ALLOCATION_ERROR;
192            goto CleanPartialInitialization;
193        }
194        current[0] = 0;
195        pieces[0] = new UnicodeString[1];
196        pieces_lengths[0] = 1;
197        if (pieces[0] == 0) {
198            status = U_MEMORY_ALLOCATION_ERROR;
199            goto CleanPartialInitialization;
200        }
201        return;
202    }
203
204
205    list = new UnicodeString[source.length()];
206    if (list == 0) {
207        status = U_MEMORY_ALLOCATION_ERROR;
208        goto CleanPartialInitialization;
209    }
210
211    // i should initialy be the number of code units at the
212    // start of the string
213    i = U16_LENGTH(source.char32At(0));
214    //int32_t i = 1;
215    // find the segments
216    // This code iterates through the source string and
217    // extracts segments that end up on a codepoint that
218    // doesn't start any decompositions. (Analysis is done
219    // on the NFD form - see above).
220    for (; i < source.length(); i += U16_LENGTH(cp)) {
221        cp = source.char32At(i);
222        if (nfcImpl.isCanonSegmentStarter(cp)) {
223            source.extract(start, i-start, list[list_length++]); // add up to i
224            start = i;
225        }
226    }
227    source.extract(start, i-start, list[list_length++]); // add last one
228
229
230    // allocate the arrays, and find the strings that are CE to each segment
231    pieces = (UnicodeString **)uprv_malloc(list_length * sizeof(UnicodeString *));
232    pieces_length = list_length;
233    pieces_lengths = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
234    current = (int32_t*)uprv_malloc(list_length * sizeof(int32_t));
235    current_length = list_length;
236    if (pieces == NULL || pieces_lengths == NULL || current == NULL) {
237        status = U_MEMORY_ALLOCATION_ERROR;
238        goto CleanPartialInitialization;
239    }
240
241    for (i = 0; i < current_length; i++) {
242        current[i] = 0;
243    }
244    // for each segment, get all the combinations that can produce
245    // it after NFD normalization
246    for (i = 0; i < pieces_length; ++i) {
247        //if (PROGRESS) printf("SEGMENT\n");
248        pieces[i] = getEquivalents(list[i], pieces_lengths[i], status);
249    }
250
251    delete[] list;
252    return;
253// Common section to cleanup all local variables and reset object variables.
254CleanPartialInitialization:
255    if (list != NULL) {
256        delete[] list;
257    }
258    cleanPieces();
259}
260
261/**
262 * Dumb recursive implementation of permutation.
263 * TODO: optimize
264 * @param source the string to find permutations for
265 * @return the results in a set.
266 */
267void U_EXPORT2 CanonicalIterator::permute(UnicodeString &source, UBool skipZeros, Hashtable *result, UErrorCode &status) {
268    if(U_FAILURE(status)) {
269        return;
270    }
271    //if (PROGRESS) printf("Permute: %s\n", UToS(Tr(source)));
272    int32_t i = 0;
273
274    // optimization:
275    // if zero or one character, just return a set with it
276    // we check for length < 2 to keep from counting code points all the time
277    if (source.length() <= 2 && source.countChar32() <= 1) {
278        UnicodeString *toPut = new UnicodeString(source);
279        /* test for NULL */
280        if (toPut == 0) {
281            status = U_MEMORY_ALLOCATION_ERROR;
282            return;
283        }
284        result->put(source, toPut, status);
285        return;
286    }
287
288    // otherwise iterate through the string, and recursively permute all the other characters
289    UChar32 cp;
290    Hashtable subpermute(status);
291    if(U_FAILURE(status)) {
292        return;
293    }
294    subpermute.setValueDeleter(uprv_deleteUObject);
295
296    for (i = 0; i < source.length(); i += U16_LENGTH(cp)) {
297        cp = source.char32At(i);
298        const UHashElement *ne = NULL;
299        int32_t el = UHASH_FIRST;
300        UnicodeString subPermuteString = source;
301
302        // optimization:
303        // if the character is canonical combining class zero,
304        // don't permute it
305        if (skipZeros && i != 0 && u_getCombiningClass(cp) == 0) {
306            //System.out.println("Skipping " + Utility.hex(UTF16.valueOf(source, i)));
307            continue;
308        }
309
310        subpermute.removeAll();
311
312        // see what the permutations of the characters before and after this one are
313        //Hashtable *subpermute = permute(source.substring(0,i) + source.substring(i + UTF16.getCharCount(cp)));
314        permute(subPermuteString.remove(i, U16_LENGTH(cp)), skipZeros, &subpermute, status);
315        /* Test for buffer overflows */
316        if(U_FAILURE(status)) {
317            return;
318        }
319        // The upper remove is destructive. The question is do we have to make a copy, or we don't care about the contents
320        // of source at this point.
321
322        // prefix this character to all of them
323        ne = subpermute.nextElement(el);
324        while (ne != NULL) {
325            UnicodeString *permRes = (UnicodeString *)(ne->value.pointer);
326            UnicodeString *chStr = new UnicodeString(cp);
327            //test for  NULL
328            if (chStr == NULL) {
329                status = U_MEMORY_ALLOCATION_ERROR;
330                return;
331            }
332            chStr->append(*permRes); //*((UnicodeString *)(ne->value.pointer));
333            //if (PROGRESS) printf("  Piece: %s\n", UToS(*chStr));
334            result->put(*chStr, chStr, status);
335            ne = subpermute.nextElement(el);
336        }
337    }
338    //return result;
339}
340
341// privates
342
343// we have a segment, in NFD. Find all the strings that are canonically equivalent to it.
344UnicodeString* CanonicalIterator::getEquivalents(const UnicodeString &segment, int32_t &result_len, UErrorCode &status) {
345    Hashtable result(status);
346    Hashtable permutations(status);
347    Hashtable basic(status);
348    if (U_FAILURE(status)) {
349        return 0;
350    }
351    result.setValueDeleter(uprv_deleteUObject);
352    permutations.setValueDeleter(uprv_deleteUObject);
353    basic.setValueDeleter(uprv_deleteUObject);
354
355    UChar USeg[256];
356    int32_t segLen = segment.extract(USeg, 256, status);
357    getEquivalents2(&basic, USeg, segLen, status);
358
359    // now get all the permutations
360    // add only the ones that are canonically equivalent
361    // TODO: optimize by not permuting any class zero.
362
363    const UHashElement *ne = NULL;
364    int32_t el = UHASH_FIRST;
365    //Iterator it = basic.iterator();
366    ne = basic.nextElement(el);
367    //while (it.hasNext())
368    while (ne != NULL) {
369        //String item = (String) it.next();
370        UnicodeString item = *((UnicodeString *)(ne->value.pointer));
371
372        permutations.removeAll();
373        permute(item, CANITER_SKIP_ZEROES, &permutations, status);
374        const UHashElement *ne2 = NULL;
375        int32_t el2 = UHASH_FIRST;
376        //Iterator it2 = permutations.iterator();
377        ne2 = permutations.nextElement(el2);
378        //while (it2.hasNext())
379        while (ne2 != NULL) {
380            //String possible = (String) it2.next();
381            //UnicodeString *possible = new UnicodeString(*((UnicodeString *)(ne2->value.pointer)));
382            UnicodeString possible(*((UnicodeString *)(ne2->value.pointer)));
383            UnicodeString attempt;
384            nfd.normalize(possible, attempt, status);
385
386            // TODO: check if operator == is semanticaly the same as attempt.equals(segment)
387            if (attempt==segment) {
388                //if (PROGRESS) printf("Adding Permutation: %s\n", UToS(Tr(*possible)));
389                // TODO: use the hashtable just to catch duplicates - store strings directly (somehow).
390                result.put(possible, new UnicodeString(possible), status); //add(possible);
391            } else {
392                //if (PROGRESS) printf("-Skipping Permutation: %s\n", UToS(Tr(*possible)));
393            }
394
395            ne2 = permutations.nextElement(el2);
396        }
397        ne = basic.nextElement(el);
398    }
399
400    /* Test for buffer overflows */
401    if(U_FAILURE(status)) {
402        return 0;
403    }
404    // convert into a String[] to clean up storage
405    //String[] finalResult = new String[result.size()];
406    UnicodeString *finalResult = NULL;
407    int32_t resultCount;
408    if((resultCount = result.count()) != 0) {
409        finalResult = new UnicodeString[resultCount];
410        if (finalResult == 0) {
411            status = U_MEMORY_ALLOCATION_ERROR;
412            return NULL;
413        }
414    }
415    else {
416        status = U_ILLEGAL_ARGUMENT_ERROR;
417        return NULL;
418    }
419    //result.toArray(finalResult);
420    result_len = 0;
421    el = UHASH_FIRST;
422    ne = result.nextElement(el);
423    while(ne != NULL) {
424        finalResult[result_len++] = *((UnicodeString *)(ne->value.pointer));
425        ne = result.nextElement(el);
426    }
427
428
429    return finalResult;
430}
431
432Hashtable *CanonicalIterator::getEquivalents2(Hashtable *fillinResult, const UChar *segment, int32_t segLen, UErrorCode &status) {
433
434    if (U_FAILURE(status)) {
435        return NULL;
436    }
437
438    //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(segment)));
439
440    UnicodeString toPut(segment, segLen);
441
442    fillinResult->put(toPut, new UnicodeString(toPut), status);
443
444    UnicodeSet starts;
445
446    // cycle through all the characters
447    UChar32 cp;
448    for (int32_t i = 0; i < segLen; i += U16_LENGTH(cp)) {
449        // see if any character is at the start of some decomposition
450        U16_GET(segment, 0, i, segLen, cp);
451        if (!nfcImpl.getCanonStartSet(cp, starts)) {
452            continue;
453        }
454        // if so, see which decompositions match
455        UnicodeSetIterator iter(starts);
456        while (iter.next()) {
457            UChar32 cp2 = iter.getCodepoint();
458            Hashtable remainder(status);
459            remainder.setValueDeleter(uprv_deleteUObject);
460            if (extract(&remainder, cp2, segment, segLen, i, status) == NULL) {
461                continue;
462            }
463
464            // there were some matches, so add all the possibilities to the set.
465            UnicodeString prefix(segment, i);
466            prefix += cp2;
467
468            int32_t el = UHASH_FIRST;
469            const UHashElement *ne = remainder.nextElement(el);
470            while (ne != NULL) {
471                UnicodeString item = *((UnicodeString *)(ne->value.pointer));
472                UnicodeString *toAdd = new UnicodeString(prefix);
473                /* test for NULL */
474                if (toAdd == 0) {
475                    status = U_MEMORY_ALLOCATION_ERROR;
476                    return NULL;
477                }
478                *toAdd += item;
479                fillinResult->put(*toAdd, toAdd, status);
480
481                //if (PROGRESS) printf("Adding: %s\n", UToS(Tr(*toAdd)));
482
483                ne = remainder.nextElement(el);
484            }
485        }
486    }
487
488    /* Test for buffer overflows */
489    if(U_FAILURE(status)) {
490        return NULL;
491    }
492    return fillinResult;
493}
494
495/**
496 * See if the decomposition of cp2 is at segment starting at segmentPos
497 * (with canonical rearrangment!)
498 * If so, take the remainder, and return the equivalents
499 */
500Hashtable *CanonicalIterator::extract(Hashtable *fillinResult, UChar32 comp, const UChar *segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
501//Hashtable *CanonicalIterator::extract(UChar32 comp, const UnicodeString &segment, int32_t segLen, int32_t segmentPos, UErrorCode &status) {
502    //if (PROGRESS) printf(" extract: %s, ", UToS(Tr(UnicodeString(comp))));
503    //if (PROGRESS) printf("%s, %i\n", UToS(Tr(segment)), segmentPos);
504
505    if (U_FAILURE(status)) {
506        return NULL;
507    }
508
509    UnicodeString temp(comp);
510    int32_t inputLen=temp.length();
511    UnicodeString decompString;
512    nfd.normalize(temp, decompString, status);
513    if (U_FAILURE(status)) {
514        return NULL;
515    }
516    if (decompString.isBogus()) {
517        status = U_MEMORY_ALLOCATION_ERROR;
518        return NULL;
519    }
520    const UChar *decomp=decompString.getBuffer();
521    int32_t decompLen=decompString.length();
522
523    // See if it matches the start of segment (at segmentPos)
524    UBool ok = FALSE;
525    UChar32 cp;
526    int32_t decompPos = 0;
527    UChar32 decompCp;
528    U16_NEXT(decomp, decompPos, decompLen, decompCp);
529
530    int32_t i = segmentPos;
531    while(i < segLen) {
532        U16_NEXT(segment, i, segLen, cp);
533
534        if (cp == decompCp) { // if equal, eat another cp from decomp
535
536            //if (PROGRESS) printf("  matches: %s\n", UToS(Tr(UnicodeString(cp))));
537
538            if (decompPos == decompLen) { // done, have all decomp characters!
539                temp.append(segment+i, segLen-i);
540                ok = TRUE;
541                break;
542            }
543            U16_NEXT(decomp, decompPos, decompLen, decompCp);
544        } else {
545            //if (PROGRESS) printf("  buffer: %s\n", UToS(Tr(UnicodeString(cp))));
546
547            // brute force approach
548            temp.append(cp);
549
550            /* TODO: optimize
551            // since we know that the classes are monotonically increasing, after zero
552            // e.g. 0 5 7 9 0 3
553            // we can do an optimization
554            // there are only a few cases that work: zero, less, same, greater
555            // if both classes are the same, we fail
556            // if the decomp class < the segment class, we fail
557
558            segClass = getClass(cp);
559            if (decompClass <= segClass) return null;
560            */
561        }
562    }
563    if (!ok)
564        return NULL; // we failed, characters left over
565
566    //if (PROGRESS) printf("Matches\n");
567
568    if (inputLen == temp.length()) {
569        fillinResult->put(UnicodeString(), new UnicodeString(), status);
570        return fillinResult; // succeed, but no remainder
571    }
572
573    // brute force approach
574    // check to make sure result is canonically equivalent
575    UnicodeString trial;
576    nfd.normalize(temp, trial, status);
577    if(U_FAILURE(status) || trial.compare(segment+segmentPos, segLen - segmentPos) != 0) {
578        return NULL;
579    }
580
581    return getEquivalents2(fillinResult, temp.getBuffer()+inputLen, temp.length()-inputLen, status);
582}
583
584U_NAMESPACE_END
585
586#endif /* #if !UCONFIG_NO_NORMALIZATION */
587